Immunosuppression following thermal injury has been noted in recent years. Both cellular and humoral immune systems have been reported to be affected. The present study aimed to compare the quantitative differences between cutaneous and electrical burn patients in respect to the partition and levels of lymphocyte populations. From March 1997 through February 1998, 15 patients with major thermal injury or high voltage electrical injury were included in this clinical prospective study. Blood samples were collected at three and seven days postburn. The evaluation of lymphocyte populations of patients was performed by SimulTest IMK plus. T cell and B cell populations, activated T cells, natural killer and helper T cell levels were all suppressed in both groups. Suppressor T cell levels were elevated in electrical burn group at both three and seven days. Therefore, CD 4/CD 8 ratios were more suppressed in electrical burn group. In conclusion, lymphocyte populations in electrical burn patients and also contributing factors which play important roles in the development of sepsis in both group need to be investigated further.